The Texas Republican is calling on his colleagues to oppose limiting debate on it, warning against what he calls procedural trickery.

"Step two is the Senate, where all accounts suggest Harry Reid plans to use procedural gimmicks to try to add funding back in for Obamacare," Cruz said. "If Reid pursues this plan — if he insists on using a 50-vote threshold to fund Obamacare with a partisan vote of only Democrats — then I hope that every Senate Republican will stand together and oppose cloture on the bill in order to keep the House bill intact and not let Harry Reid add Obamacare funding back in."

"Now is a time for party unity; Senate Republicans should stand side-by-side with courageous House Republicans," Cruz said.

The statement underscores the unwinnable procedural hand faced by conservative senators, however. They know that Senate Majority Leader Harry Reid will move to strike out the Obamacare defunding language after getting the 60 votes needed to limit debate, but they can't stop him without effectively endorsing a government shutdown.

The Nevada Democrat's move is completely in keeping with long-standing Senate rules. Pending germane amendments and motions, such as a motion to strike, are allowed simple-majority votes after debate's been limited.

"Republicans are simply postponing for a few days the inevitable choice they must face: pass a clean bill to fund the government, or force a shutdown. I have said it before but it seems to bear repeating: The Senate will not pass any bill that defunds or delays Obamacare," Reid said in a Friday statement.

Cruz's statement also came shortly after the head of the Senate Conservatives Fund said likewise.

"Harry Reid needs 60 votes to approve his plan to fund Obamacare. If 41 Republicans stand strong and oppose cloture, they can defeat Reid's plan to fund Obamacare. However, if Republicans waffle and vote for cloture, it will grease the skids for Reid's plan to fund Obamacare. It's pretty simple — any Republican who votes for cloture is voting to fund Obamacare," SCF Executive Director Matt Hoskins said.

By asking Republicans to oppose any motion to invoke cloture, and thus limit debate, on the stopgap spending bill passed Friday by the Republican-led House — the one that does defund the health care overhaul — Cruz and Hoskins are literally calling for Republicans to filibuster the bill and, possibly, shut down the government in the process.

Hoskins goes directly at Minority Leader Mitch McConnell, R-Ky.

"It's time for Mitch McConnell to show some leadership and deliver the 41 votes needed to defeat cloture on Harry Reid's plan to fund Obamacare," Hoskins said. "Republicans like to say they are against Obamacare, but now is the time to prove it. Now is when it matters."

Of course, if GOP senators actually follow Cruz and Hoskins' advice, they will, in effect, be voting against a bill that includes Obamacare defunding. The vote to strike that language is not expected until after cloture is invoked, and it will take only 51 votes to succeed. That's why Cruz may ultimately be proved correct when he says Democrats have the votes to send the measure back to the House, without Obamacare funding.